The proposed research seeks to advance knowledge about the contribution of auditory cortex to basic psychoacoustic functions (e.g. frequency discrimination) in relation to speech, music, and voice perception. The results could lead to new approaches in the diagnosis and treatment of sensory aphasia, congenital auditory disorders, and related syndromes. Prospective, quantitative analyses of perceptual deficits and pathoanatomical correlates will be undertaken in stroke patients and temporal lobectomy patients with lesions of auditory cortex and connected structures. The proposed experiments build on previous work in psychoacoustics, neurology, and neuroanatomy. Studies of control populations also will provide an opportunity to estimate the variance in psychoacoustic functions among normal adults. The experimental series includes measurements of critical bandwidth, frequency discrimination, intensity discrimination, virtual pitch perception, inharmonicity detection, auditory priming, roughness detection, and frequency pattern discrimination. The location and volume of strokes and temporal lobe excisions will be analyzed using multiplanar, multisequence MRI. In addition, pre-operative PET will be used to analyze glucose hypometabolism in the superior temporal lobe of complex partial seizure patients with ipsilateral medial temporal lobe foci.